In the heavy equipment industry there has been a pressing need for versatility in the operation of certain vehicles. This has been accomplished by using a single vehicle for multiple functions. As a result, many different implements have been designed to be coupled to a support frame carried by the lift arms of a vehicle such as a wheel loader. To enhance their versatility even more, a coupling mechanism has been provided that will allow the various implements to be coupled and uncoupled very expediently.
These couplings often have mounted to the support frame, one or more hydraulic cylinders that, when actuated, drive a plurality of mounting pins laterally into aligned bores that exist in both the support frame and work elements. This can most often be accomplished from the cab of the vehicle which is in keeping with the theme of versatility that makes these types of machines so desirable. There are instances however, such as during alignment of the support frame with the implement, that the operator does not have an absolutely clear view of both components. Sometimes the initial contact between the support frame and the implement is done by "feel" and leaves the actual connection of the two elements to the operator's experience. This presents a problem in being able to tell whether or not the bores of the respective elements are properly aligned and whether or not the mounting pins have been properly placed within the aligned bores. Often times the only way to know if a connection has been made is to move the vehicle slightly or perform some initial control functions to be certain that the implement is mounted properly. If a secure coupling has not been achieved then the entire process must be repeated thus negating some of the valuable time saved by the intended versatility of the machine.
A typical coupling apparatus as described above is disclosed in U.S. Pat. No. 3,272,264 issued to H. S. Antolini on Sept. 13, 1966. The patent discloses a latching arrangement between a frame and an earthworking tool that incorporates a plurality of mounting pins that are mounted within the frame. The pins are aligned with bores formed in the tool and upon actuation of a single hydraulic cylinder, the pins are driven laterally by a linkage arrangement to engage the bores of the tool and secure it to the frame. There is no indication upon actuation of the cylinder whether or not the mounting pins properly engaged the bores of the tool.
Another coupling apparatus is disclosed in U.S. Pat. No. 3,876,091, issued to Raymore D. MacDonald on Apr. 8, 1975. This patent also discloses a plurality of mounting pins that are mounted within a framework that is supported on the ends of a pair of lift arms of a vehicle. The mounting pins are extended laterally into aligned openings formed in a work implement upon actuation of a centrally mounted lever. While the position of the lever may serve as an indication as to whether or not the pins have been laterally displaced, there is no indication that the pins have been seated properly within the bores.
Another coupling apparatus that is similar to those previously described is disclosed in U.S. Pat. No. 3,760,883 issued to Billy D. Birk on Sept. 25, 1973. This patent also discloses a plurality of laterally extendable pins that are mounted to a support frame that engage aligned bores of a work implement to achieve coupling thereof to the support frame. This patent also fails to disclose a means to indicate the position of the pins or their relationship with respect to the work implement.
Yet another coupling means for loader attachments is disclosed in U.S. Pat. No. 3,243,066, issued to C. W. Gardner et al on Mar. 29, 1966. This patent also discloses a plurality of mounting pins that are mounted to a support frame and extend laterally into aligned mounting holes of an attachment. A means is provided that visually indicates that the pins have moved to their extended position however the indicating means does not indicate whether or not a proper coupling between the support frame and the attachment has been achieved.
The present invention is directed to overcoming one or more of the problems as set forth above.